Despite their compact design, impact drivers can cost you a pretty penny, especially if you want extras like more batteries.• You'll need bits that are compatible with impact drivers. Due to the enormous torque delivered by an impact driver, normal drill bits wear out very quickly. So you may want to purchase some parts meant to work specifically with impact drivers. • Because they are compact and not intended for drilling holes, impact drivers do not come with 3-jaw chucks. Basically this means that your impact driver may not be able to hold most drill bits; which means you will need to purchase specific drill bits for your impact driver. • Impact drivers do not have torque control. Torque control is a feature found on most cordless drills that allows you to choose the amount of torque to apply when you press the trigger on the drill. When used correctly, it helps prevent the drill from damaging the screws and the surface you are drilling on. Because they don't have torque control, you'll need to be extra careful when using an impact driver, otherwise you'll have a lot of gaping screws and damaged surfaces on your hands. What to look for when buying an impact driverBattery